Coil component and method for manufacturing same

ABSTRACT

A coil component of the present invention includes a magnetic core containing magnetic powder, a coil element embedded in the magnetic core and having an end projecting from the magnetic core, and a retaining member for retaining the end of the coil element. The retaining member has a main surface having a recess therein sinking toward the magnetic core. The retaining member has a ridge projecting from a bottom surface of the recess and extending linearly along the bottom surface. The ridge has a portion that intersects with the end of the coil element. The portion of the ridge is welded to the end of the coil element.

TECHNICAL FIELD

The present invention relates to a coil component used for variouselectronic devices, and a method for manufacturing the coil component.

BACKGROUND ART

In recent years, electronic components have been required to have smallsizes and used with large currents as performance of electronic devicesis highly developed. The electronic components include a coil component.

FIG. 17 is a perspective view of conventional coil component 5.Conventional coil component 5 includes coil element 1 made of aninsulation-coated copper wire which is wound. An end of coil element 1is welded to retaining members 3. Coil element 1 and retaining member 3are pressure-molded integrally with mixed powder containing metallicmagnetic powder and binding agent containing thermosetting resin, andpartially embedded in magnetic core 2. Terminal 4 is formed by bendingthe end of coil element 1 and a portion of retaining member 3 projectingfrom a side surface of magnetic core 2.

PTL 1 is known as a prior art document relating to this application.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Laid-Open Publication No. 2013-191726

SUMMARY

In order to provide coil component 5 shown in FIG. 17 with a small size,retaining member 3 has a small size. However, it is necessary to reducethe thickness of retaining member 3 to provide retaining member 3 with asmall size. If the thickness is reduced, retaining member 3 may bedistorted at welding. For instance, when retaining member 3 is welded tothe end of coil element 1, retaining member 3 has a distortion.Especially, a resistance welding may cause a large distortion inretaining member 3. In the resistance welding, welding electrodessandwich the end of coil element 1 and retaining member 3 between theelectrodes to press. When the welding electrodes apply a pressure,retaining member 3 is elongated in a direction perpendicular to adirection in which the end of coil element 1 extends, thereby causingdistortion. The distortion of retaining member 3 may be an obstacle fora metallic mold to perform proper molding when a magnetic material andretaining member 3 are pressure molded. Alternatively, it may beconsidered to increase a clearance of a metallic mold, but theconsideration is undesirable because a leak of magnetic materials occursat the pressure molding, and thus causes deterioration in productivity.

In view of the above problem in conventional coil component 5, a coilcomponent according to the present invention includes a magnetic corecontaining binding agent and magnetic powder mixed into the bindingagent, a coil element embedded in the magnetic core, and a retainingmember for retaining an end of the coil element. The end of the coilelement projects from the magnetic core. The retaining member has arecess therein sinking toward the magnetic core. The retaining memberhas a ridge projecting from a bottom surface of the recess and extendinglinearly along the bottom surface. The ridge has a portion intersectingwith the end of the coil element, and is welded to the end of the coilelement at the portion.

The above configuration prevents distortion from occurring in theretaining member, and provides the coil component with high productivityeven if the coil component has a small size.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view of a coil component in accordancewith an exemplary embodiment of the present invention.

FIG. 2 is a perspective view of the coil component in accordance withthe embodiment.

FIG. 3 is a cross-sectional view of the coil component along lineIII-III shown in FIG. 2.

FIG. 4 is a cross-sectional view of the coil component along line IV-IVshown in FIG. 2.

FIG. 5 is a side view of the coil component shown in FIG. 2 forillustrating a retaining member.

FIG. 6 is a perspective view of a coil component in accordance with anexemplary embodiment.

FIG. 7 is a side view of the coil component shown in FIG. 6 forillustrating a retaining member.

FIG. 8 is a perspective view of a coil component in accordance with anexemplary embodiment.

FIG. 9 is a side view of the coil component shown in FIG. 8 forillustrating a retaining member.

FIG. 10 shows a method for manufacturing the coil component shown inFIG. 2.

FIG. 11 shows the method for manufacturing the coil component shown inFIG. 2.

FIG. 12 shows the method for manufacturing the coil component shown inFIG. 2.

FIG. 13 shows the method for manufacturing the coil component shown inFIG. 2.

FIG. 14 shows the method for manufacturing the coil component shown inFIG. 2.

FIG. 15 shows the method for manufacturing the coil component shown inFIG. 2.

FIG. 16 shows the method for manufacturing the coil component shown inFIG. 6.

FIG. 17 is a perspective view of a conventional coil component.

DETAIL DESCRIPTION OF PREFERRED EMBODIMENTS Exemplary Embodiment 1

FIG. 1 is an exploded perspective view of coil component 10 inaccordance with Exemplary Embodiment 1.

Coil component 10 in accordance with the present embodiment includesmagnetic core 11 containing metallic magnetic powder and binding agentcontaining thermosetting resin, coil element 12 formed by winding a leadwire helically, and retaining member 13 for electrically connecting toan external terminal. A winding part of coil element 12 is embedded inmagnetic core 11 while and end 12 a of coil element 12 is exposed frommagnetic core 11. End 12 a of coil element 12 is electrically connectedto retaining member 13 by welding. Retaining member 13 is partiallyembedded and fixed in magnetic core 11.

FIG. 2 is a perspective view of coil component 10 seeing throughmagnetic core 11. The outline of magnetic core 11 is illustrated by thebroken line. FIG. 3 is a cross-sectional view of coil element 12 alongline III-III shown in FIG. 2 in which retaining member 13 is welded toend 12 a of coil element 12. FIG. 4 is a cross-sectional view of thecoil component along line IV-IV shown in FIG. 2 for illustratingretaining member 13 welded to end 12 a of coil element 12. FIG. 5 is aside view of the coil component shone in FIG. 2 for illustratingretaining member 13.

Magnetic core 11 shown in FIG. 2 includes pressurized powder body 19 aand pressurized powder body 19 b shown in FIG. 1.

The binding agent containing thermosetting resin is mixed with metallicmagnetic powder while the thermosetting resin is not fully cured, andpressure molded at a molding pressure of about 1 ton/cm² to formpressurized powder body 19 a and pressurized powder body 19 b.

Pressurized powder body 19 b has a rectangular columnar shape havingtherein accommodating part 119 b for accommodating coil element 12therein. Pressurized powder body 19 a has a lid shape to be put onpressurized powder body 19 b. Coil element 12 is accommodated inaccommodating part 119 b serving as a hollow provided in pressurizedpowder body 19 b. Pressurized powder bodies 19 a and 19 b are pressuremolded again while coil element 12 is disposed between pressurizedpowder body 19 a and pressurized powder body 19 b, thereby providingmagnetic core 11. At this moment, the second pressure molding is carriedout at a molding pressure of about 5 ton/cm² which is larger than themolding pressure at the first pressure molding. The thicknesses ofpressurized powder body 19 a and pressurized powder body 19 b after thesecond pressure molding is smaller than thicknesses of pressurizedpowder body 19 a and pressurized powder body 19 b before the secondpressure molding. That is, the density of pressurized powder body 19 aand pressurized powder body 19 b after the second pressure molding islarger than the density of pressurized powder body 19 a and pressurizedpowder body 19 b before the second pressure molding. The second pressuremolding allows coil element 12 to be embedded in pressurized powder body19 a and pressurized powder body 19 b, thereby providing magnetic core11 in which end 12 a of the coil element 12 and retaining member 13project from the boundary between pressurized powder body 19 a andpressurized powder body 19 b. Subsequently, the thermosetting resincontained in magnetic core 11 is fully cured by heat-treatment.

Coil element 12A is formed by winding a copper wire with a surfacecoated with insulation to have a coil form. In accordance with theembodiment, coil element 12 has a diameter of 0.3 mm. The insulationcoating the surface of end 12 a of coil element 12 is removed previouslyby the time when end 12 a is electrically connected to ridge 17 bywelding described later. End 12 a of coil element 12 is pressed to havea flat shape with a thickness of about 0.2 mm.

In accordance with the embodiment, a copper plate with a thickness ofabout 0.15 mm is punched to form retaining member 13. Two retainingmembers 13 extending along two side surfaces of magnetic core 11opposite to each other are bent along a lower surface of the magneticcore 11. One retaining member 13 out of two retaining members 13 hasprojecting portions 21 a and 21 b projecting from both sides of an endof retaining member 13. Another retaining member 13 out of two retainingmembers 13 has projecting portions 21 c and 21 d projecting from bothsides of an end of retaining member 13. Projecting portions 21 a, 21 b,21 c, and 21 d are embedded and fixed in magnetic core 11.

A surface of retaining member 13 projecting from magnetic core 11 may becoated with solder by solder dipping, if necessary. Retaining member 13constitutes terminal part 20 together with end 12 a of coil element 12,and is connected to an external terminal.

Retaining member 13 has recess 18 therein. Recess 28 is formed such thatan area of retaining member 13 including a portion of retaining member13 where retaining member 13 and end 12 a of coil element 12 overlapsinks toward magnetic core 11 from the remaining area of retainingmember 13. Retaining member 13 has main surface 113 a having recess 18formed therein. In accordance with the embodiment, a depth of recess 18is about 0.2 mm. Retaining member 13 has ridge 17 projecting from bottomsurface 22 of recess 18.

As shown in FIG. 5, ridge 17 extends linearly as to intersect with anextending direction in which end 12 a of coil element 12 extends. Recess18 is embossed from a back surface of recess 22 opposite to bottomsurface 22 to form ridge 17. Upon being welded by resistance weldingwhile ridge 17 intersects with end 12 a of coil element 12, ridge 17 iselectrically connected to end 12 a of coil element 12 by the welding.

A length of ridge 17 is larger than a width of end 12 a of coil element12. In accordance with the embodiment, ridge 17 has a height of 0.1 mmprojecting from bottom surface 22.

According to the embodiment, as shown in FIGS. 2 and 3, recess 18 isembossed from the back surface of recess 18 opposite to bottom surface22 to form ridge 17. Groove 17 a is formed in the back surface of ridge17 along the shape of ridge 17 by the embossing. Since groove 17 aextends along the shape of ridge 17 in the back surface of ridge 17,welding pressure easily distorts and crushes ridge 17 when ridge 17 iswelded to end 12 a of coil element 12 by resistance welding. Thisprevents projecting portions 21 a, 21 b, 21 c, and 21 d from expandingin direction 24 of retaining member 13, thereby reducing a clearancebetween a die and retaining member 13.

As a result, even if being made of soft material with high conductivity,such as copper, retaining member 13 can be thin, thereby providing coilcomponent 10 with a small size.

Direction 23 shown in FIG. 2 is perpendicular to the lower surface ofcoil component 10 (magnetic core 11) while direction 24 is parallel tothe lower surface of coil component 10 and the side surface of magneticcore 11 accommodating retaining member 13.

According to the embodiment, a cross section of ridge 17 in a directionperpendicular to the direction in which ridge 17 extends preferably hasa projection shape tapering from a root portion to a tip end of ridge17. The cross section of ridge 17 preferably has, e.g. a triangularshape, a circular arc shape, and a trapezoidal shape. The above shape ofridge 17 allows a current to concentrate and flow into a top of ridge 17when ridge 17 is welded by resistance welding. Therefore, end 12 a ofcoil element 12 can be welded to retaining member 13 stably.

According to the embodiment, when retaining member 13 is distorted,projecting portions 21 a and 21 b may be distorted in direction 24 inwhich the projecting portions are separated from each other and caughtby a die at the second pressure welding. Further, projecting portions 21c and 21 d may be distorted similarly. To solve this problem, ridge 17has the projecting cross section, and extends linearly in the directionin which ridge 17 intersects with end 12 a of coil element 12. Thus, adirection of stress crushing and widening ridge 17 can be directed indirection 23. This configuration easily elongates ridge 17 in direction23, and prevents projecting portions 21 a, 21 b, 21 c, and 21 d ofretaining member 13 from being distorted in direction 24.

Accordingly, ridge 17 intersecting perpendicularly with end 12 a of coilelement 12 in the direction in which end 12 a of coil element 12 extendsfurther prevents projecting portions 21 a, 21 b, 21 c, and 21 d ofretaining member 13 from being distorted in the direction 24.

As shown in FIG. 4, in accordance with the embodiment, ridge 17projecting from bottom surface 22 of recess 18 is provided in recess 18.

Since ridge 17 is provided in recess 18, the distortion caused whenridge 17 deforms can hardly transmit to main surface 113 a of theretaining member 13 around recess 18.

Further, the height of ridge 17 projecting from bottom surface 22 ofrecess 18 may be not larger than two thirds of the depth of recess 18.This configuration prevents the distortion caused when ridge 17 deformsfrom transmitting to main surface 113 a of the retaining member 13.

Exemplary Embodiment 2

FIG. 6 is a perspective view of coil component 10 a in accordance withExemplary Embodiment 2. A broken line in FIG. 6 denotes the outline ofmagnetic core 11. FIG. 7 is a side view of the coil component forshowing retaining member 13 shown in FIG. 6.

In FIGS. 6 and 7, components identical to those of coil component 10according to Embodiment 1 shown in FIGS. 1 to 5 are denoted by the samereference numerals.

As shown in FIG. 7, in coil component 10 a, retaining member 13 hasslits 14 slit 15 passing through retaining member 13. End 12 a of coilelement 12 and ridge 17 are disposed between slits 14 and 15.

Since end 12 a of coil element 12 and ridge 17 are disposed betweenslits 14 and 15, coil component 10 a reduces stress which is caused whenretaining member 13 is welded to end 12 a of coil element 12 byresistance welding and which transmits in direction 24 of retainingmember 13. In coil component 10 a according to the present embodiment,slit 14 and slit 15 have longer sides parallel to each other, and haverectangular shapes having lengths in direction 23 of about 1.2 mm andlengths in direction 24 of about 0.3 mm. A distance between slit 14 andslit 15 is about 1 mm.

Retaining member 13 further has slit 16 passing through retaining member13. Slit 16 is provided in an area which is between slit 14 and slit 15and which extends in a direction in which end 12 a of coil element 12extends. Slit 16 is provided in the area extending in the direction inwhich end 12 a of coil element 12 extends. Slit 16 reduces thedistortion of retaining member 13 in direction 23 which is caused whenretaining member 13 is welded to end 12 a of coil element 12 byresistance welding.

In accordance with the present embodiment, slit 16 has a rectangularshape having a length in direction 24 of about 0.6 mm and a length indirection 23 of about 0.3 mm. A distance between slit 16 and slit 14 anda distance between slit 16 and slit 15 are about 0.5 mm.

As shown in FIG. 7, retaining member 13 has step portion 13 a (inside anarea surrounded by a broken line), step portion 13 b (inside an areasurrounded by a broken line), and step portion 13 c (inside an areasurrounded by a broken line) which are connected to main surface 113 aof retaining member 13 and bottom surface 22 of recess 18. Step portions13 a, 13 b and 13 c constitute a step around recess 18. End 12 a of thecoil element 12 and ridge 17 are disposed between step portions 13 a and13 b opposite to each other.

Step portion 13 c is provided in an area that is between slit 14 andslit 15 and that extends in the direction in which end 12 a of coilelement 12 extends. Slits 14, 15, and 16 passes in along step portions13 a, 13 b, and 13 c, respectively, thereby forming recess 18 easily.

Exemplary Embodiment 3

FIG. 8 is a perspective view of coil component 10 b in accordance withExemplary Embodiment 3. A broken line in FIG. 8 denotes the outline ofmagnetic core 11. FIG. 9 is a side view of the coil component forillustrating retaining member 13 shown in FIG. 8. In FIGS. 8 and 9,components identical to those of coil components 10 and 10 a accordingto Embodiments 1 and 2 are denoted by the same reference numerals. Coilcomponent 10 b according to Embodiment 3 is different from coilcomponent 10 a according to Embodiment 2 in that widths of portions ofslit 14 and slit 15 in a direction perpendicular to a direction in whichslit 14 and slit 15 slenderly extend change depending on the positionsof the portions.

The widths of slit 14 and slit 15 in the direction in which slit 14 andslit 15 extend will be described with referring to FIG. 9.

Slits 14 has both end portions 14 a and 14 b in direction 23 in whichslit 14 slenderly extends. End portion 14 a, out one of the both endportions, is located close to position P1 (see FIGS. 9 and 3) at whichend 12 a of coil element 12 projects from magnetic core 11. End portion14 b, the other of the both ends portion, is located farther fromposition P1 than end portion 14 a is. The width of end portion 14 a islarger than the width of end portion 14 b. This configuration allowssolder to easily enter in slit 14 when retaining member 13 is dippedinto the solder, thereby increases the strength of terminal area 20.

That is, slit 14 has end portion 14 a which has a width larger than thatof end portion 14 b. A distance between end portion 14 b and position P1at which end 12 a of coil element 12 projects from magnetic core 11 islarger than a distance between end portion 14 a and position P1.

The width of slit 14 increases monotonically from end portion 14 b, theother of the both end portions, to portion 14 a, one of the both endportions. This configuration allows solder to enter in slit 14 moreeasily, thereby increasing strength of terminal area 20.

According to the present embodiment, the width of slit 14 is 0.3 mm atend portion 14 a, one of the both end portions located close to positionP1 at which end 12 a of coil element 12 projects from magnetic core 11,and the width of slit 14 is 0.2 mm at end portion 14 b, the other of theboth end portions.

Slit 15 has the same shape as slit 14.

That is, slit 15 has both end portions 15 a and 15 b of in direction 23in which slit 15 slenderly extends. End portion 15 a, one of the bothend portions, is located close to position P1 (see FIGS. 9 and 3) atwhich end 12 a of coil element 12 projects from magnetic core 11. Endportion 15 b, the other of the both end portions, is located fartherfrom position P1 than end portion 15 a is. A width of end portion 15 ais larger than that of end portion 15 b. This configuration allowssolder to easily enter into slit 15 when retaining member 13 is dippedinto the solder, thereby increasing strength of terminal area 20.

That is, slit 15 has end portion 15 a which has a width larger than thatof end portion 15 b. A distance between end portion 15 b and position P1at which end 12 a of coil element 12 projects from magnetic core 11 islarger than a distance between end portion 15 a and position P1.

The width of slit 15 increases monotonically from end portion 15 b, theother of the both end portions, to end portion 15 a, one of the both endportions. This configuration allows solder to enter into slit 15 moreeasily, thereby increasing strength of terminal area 20.

According to the exemplary embodiment, the width of slit 15 is 0.3 mm atend portion 15 a, one of the both end portions located close to positionP1 at which end 12 a of coil element 12 projects from magnetic core 11,and the width of slit 15 is 0.2 mm at end portion 15 b, the other of theboth end portions. This configuration allows solder to enter into slit15 more easily, thereby increasing strength of terminal area 20.

(Method for Manufacturing Coil Component 10 in Accordance withEmbodiment 1)

A method for manufacturing coil component 10 in accordance withEmbodiment 1 shown in FIG. 2 will be described below.

FIG. 10 is a perspective view of coil element 12 to be embedded inmagnetic core 11 of coil component 10 in accordance with Embodiment 1.As shown in FIG. 10, a copper wire with a diameter of 0.3 mm having asurface coated with insulation is wound helically to provide coilelement 12. Two ends 12 a of coil element 12 extend in directionsopposite to each other. The insulation coating end 12 a of coil element12 therewith is removed before end 12 a is electrically connected toretaining member 13. End 12 a of coil element 12 is pressed to have aflat shape having a thickness in the pressing direction of about 0.2 mm.Since being pressed to have the flat shape, end 12 a of coil element 12is prevented from projecting outward from recess 18, thereby preventingoverall dimensions of coil component 10 from increasing.

In the case that coil element 12 is made of a copper wire having a smalldiameter, end 12 a of coil element 12 may necessarily be pressed.

FIG. 11 is a perspective view of retaining member 13 connected to ahoop. As shown in FIG. 11, a copper plate is punched by using a die toprovide retaining member 13 connected to a hoop. At this moment,retaining member 13 is pressed to form recess 18 sinking from mainsurface 113 a of retaining member 13 by a depth of about 0.2 mm. Then,recess 18 is embossed from a back surface of recess opposite to bottomsurface 22 to form ridge 17 on bottom surface 22 of recess.

In accordance with Embodiment 1, a height of ridge 17 projecting frombottom surface 22 of recess 18 is 0.1 mm, and ridge 17 has a linearshape which intersects perpendicularly with end 12 a of coil element 12.Ridge 17 may be formed by pressing simultaneously when recess 18 ispressed.

Groove 17 a extending linearly (see FIGS. 1 and 2) is formed in a backsurface of ridge 17 by the above embossing. Further, two retainingmembers 13 have respective end portions facing each other. Projectingportions 21 a and 21 b are provided at both sides of one of therespective end portions of two retaining members 13. Projecting portions21 c and 21 d are provided at both sides of another of the respectiveend portions of two retaining members 13. Projecting portions 21 a, 21b, 21 c, and 21 d are embedded in magnetic core 11 and fixed whenmagnetic core 11 is subjected to the second-pressure molding describedlater.

FIG. 12 is a perspective view of coil element 12 having end 12 a fixedto retaining member 13 shown in FIG. 11.

As shown in FIG. 12, end 12 a of coil element 12 is put into recess 18,and end 12 a of coil element 12 and ridge 17 cross and are placed oneach other. Then, coil element 12 is fixed to retaining member 13 byresistance welding.

FIG. 13 is a perspective view of magnetic core 11 in which coil element12 and projecting portions 21 a, 21 b, 21 c, and 21 d of two retainingmembers 13 shown in FIG. 12 are embedded. In FIG. 13, the outline ofmagnetic core 11 is denoted by a broken line. A method for manufacturingmagnetic core 11 will be described below.

First, binding agent containing thermosetting resin is mixed to metallicmagnetic powder to provide mixed material. The mixed material is driedsuch that the thermosetting resin is not fully cured, and then, crushedinto particles to provide magnetic material powder. The magneticmaterial powder is pressure molded at about 1 ton/cm² to formpressurized powder body 19 a and pressurized powder body 19 b shown inFIG. 1.

Next, pressurized powder body 19 a is placed on pressurized powder body19 b such that coil element 12 and projecting portions 21 shown in FIG.12 are disposed between pressurized powder bodies 19 a and 19 b, andthen, pressurized powder bodies 19 a and 19 b are unified by the secondpressure molding. The second pressure molding is carried out at about 5ton/cm².

The above processes provides magnetic core 11 denoted by the broken lineshown in FIG. 13. Coil element 12 and projecting portions 21 a, 21 b, 21c, and 21 d are embedded in magnetic core 11. Subsequently, magneticcore 11 is heat-treated at 180° C. to fully cure the thermosetting resincontained in pressurized powder bodies 19 a and 19 b.

FIG. 14 is a perspective view of retaining member 13 after retainingmember 13 shown in FIG. 13 is separated from a hoop. A broken linedenotes the outline of magnetic core 11.

As shown in FIG. 14, two retaining members 13 fixed to magnetic core 11are separated from the hoop to provide individual pieces. End 12 a ofretaining member 13 and coil element 12 are coated with a flux and thendipped into solder. As a result, retaining member 13 and end 12 a ofcoil element 12 are connected with solder.

The above processes provide coil component 10.

FIG. 15 is a perspective view of coil component 10 in which tworetaining members 13 shown in FIG. 14 extend along two side surfaces ofmagnetic core 11, and bent on the lower surface of coil component 10.

As shown in FIG. 15, retaining member 13 which is separated into anindividual piece shown in FIG. 14 is cut to have a predetermined length,and the back surface of recess 18 opposite to bottom surface 22 ofrecess 18 is bent along the side surface of the magnetic core 11.

Then, retaining members 13 are bent toward the lower surface of magneticcore 11 to provide coil component 10 shown in FIG. 15. A recess may beformed in the side surface of magnetic core 11 to have recess 18 of theretaining member 13 fit into the recess.

(Method for Manufacturing Coil Component 10 s in Accordance withEmbodiment 2)

Next, a method for manufacturing coil component 10 a in accordance withExemplary Embodiment 2 shown in FIG. 6 will be described below.

A difference between the manufacturing methods according to Embodiments1 and 2 is that whether a slit is provided in retaining member 13 ornot.

Hereinafter, description about the same manufacturing method asEmbodiment 1 is omitted.

FIG. 16 is a perspective view of retaining member 13 having slits 14,15, and 16 provided in retaining member 13 in FIG. 12.

As shown in FIG. 16, retaining member 13 in accordance with Embodiment 2has slits 14 and 15 such that end 12 a of coil element 12 and ridge 17are disposed between slits 14 and 15. Slit 16 is provided in an areathat is between slit 14 s and 15 and extends in the direction in whichend 12 a of coil element 12 extends.

Slits 14, 15, and 16 are formed by punching retaining member 13 whilebeing connected to the hoop shown in FIG. 11.

As shown in FIGS. 6 and 7, slit 14 is formed in along step portion 13 a,slit 15 is formed in along step portion 13 b, and slit 16 is formed inalong step portion 13 c, thereby allowing recess 18 to be formed easily.

In the method for manufacturing coil component 10 a according toEmbodiment 2 shown in FIG. 6, coil component 10 b according toEmbodiment 3 shown in FIG. 8 can be formed by adjusting a slit to bepunched in shape suitably when retaining member 13 connected to the hoopis punched.

INDUSTRIAL APPLICABILITY

A coil component in accordance with the present invention can reduceclearance between a die and a retaining member even if having a smallsize, and is useful as a coil component with high productivity.

REFERENCE MARKS IN THE DRAWINGS

10, 10 a, 10 b coil component11 magnetic core12 coil element12 a end of coil element13 retaining member13 a step portion (first step portion)13 b step portion (second step portion)13 c step portion (third step portion)14 slit (first slit)14 a end portion (second portion)14 b end portion (first portion)15 slit (second slit)15 a end portion (fourth portion)15 b end portion (third portion)16 slit (third slit)17 ridge17 a groove18 recess19 a pressurized powder body19 b pressurized powder body20 terminal area21 a projecting portion21 b projecting portion21 c projecting portion21 d projecting portion22 bottom surface

1. A coil component comprising: a magnetic core containing magneticpowder; a coil element embedded in the magnetic core, the coil elementhaving has an end projecting from the magnetic core; and a retainingmember for retaining the end of the coil element, wherein the retainingmember has a main surface having a recess therein sinking toward themagnetic core, wherein the retaining member has a ridge projecting froma bottom surface of the recess and extending linearly along the bottomsurface, and wherein the ridge has a portion that intersects with theend of the coil element, and is welded to the end of the coil element atthe portion of the ridge.
 2. The coil component according to claim 1,wherein the ridge is provided in the recess.
 3. The coil componentaccording to claim 1, wherein the retaining member has a first slit anda second slit arranged such that the end of the coil element and theridge are provided between the first slit and the second slit.
 4. Thecoil component according to claim 3, wherein the recess has a first stepportion and a second step portion which are connected to the mainsurface of the retaining member and the bottom surface of the recess,wherein the first slit passes in along the first step portion of therecess, and wherein the second slit passes in along the second stepportion of the recess.
 5. The coil component according to claim 3,wherein the first slit has a first portion and a second portion, thefirst portion of the first slot having a first width, the second portionof the first slit having a second width larger than the first width,wherein a distance between a position at which the end of the coilelement projects from the magnetic core and the first portion of thefirst slit is larger than a distance between the position and the secondportion of the first slit, wherein the second slit has a third portionand a fourth portion, the third portion of the second slit having athird width, the fourth portion of the second slit having a fourth widthlarger than the third width, and wherein a distance between the positionand the third portion of the second slit is larger than a distancebetween the position and the fourth portion of the second slit.
 6. Thecoil component according to claim 5, wherein the first portion of thefirst slit includes one of both ends of the first slit, and the secondportion includes another of the both ends of the first slit, wherein awidth of the first slit monotonically increases from the first portionto the second portion of the first slit, wherein the third portion ofthe second slit includes one of both ends of the second slit, and thefourth portion includes another of the both ends of the second slit, andwherein a width of the second slit monotonically increases from thethird portion to the fourth portion of the second slit.
 7. The coilcomponent according to claim 3, wherein the retaining member has a thirdslit between the first slit and the second slit, the third slit extendsin a direction in which the end of the coil element extends.
 8. The coilcomponent according to claim 7, wherein the recess has a step portionconnected to the main surface of the retaining member and the bottomsurface of the recess, and wherein the third slit passes in along thestep portion of the recess.
 9. A method for manufacturing a coilcomponent, comprising: providing a coil element including a wound leadwire having an end; providing a retaining member made of a flat metalplate having a recess therein, the retaining member having a ridgeprojecting from a bottom surface of the recess and extending linearlyalong the bottom surface; disposing the retaining member and the coilelement to allow the ridge to have a portion intersecting with the endof the coil element; welding the portion of the ridge with the end ofthe coil element; and pressure molding a magnetic core made of amagnetic material while the coil element is embedded in the magneticcore.
 10. The method according to claim 9, further comprising bendingthe retaining member.
 11. The method according to claim 9, wherein theretaining member has a first slit and a second slit arranged such thatthe end of the coil element and the ridge are disposed between the firstslit and the second slit.
 12. The method according to claim 11, whereinthe first slit passes in along a first step portion of the recessconnected to the main surface of the retaining member and the bottomsurface of the recess, and wherein the second slit passes in along asecond step portion of the recess connected to the main surface of theretaining member and the bottom surface of the recess.
 13. The methodaccording to claim 11, wherein the retaining member has a third slitbetween the first slit and the second slit, the third slit extending ina direction in which the end of the coil element extends.
 14. The methodaccording to claim 13, wherein the third slit passes in along a thirdstep portion of the recess connected to the main surface of theretaining member and the bottom surface of the recess.